Conventionally, a manufacture of rice confectionery products represented by Japanese rice crackers comprises steps as follows: compounding and kneading pulverized raw material rice (non-glutinous and glutinous rice) under vapor (the step may also be called “steaming and kneading”); rolling the products using a rolling roller in a variety of thicknesses; and cutting the rolled products into a variety of uniform shapes using a shape cutting roller. Thereafter, the cut-out rice confectionery dough pieces are dried and water content thereof is adjusted by being arranged in lines on a transporting conveyor belt and being transported inside a drying compartment under a hot blast atmosphere, before they go through a step of baking inside a baking apparatus. However, a maturing step is normally arranged prior to baking inside the baking apparatus, so that differences in water content between the interior and exterior of a single rice confectionery dough piece dried using the drying apparatus, and varied water content between each of the rice confectionery dough pieces, which arises from drying the products arranged in lines on the transporting conveyor belts under a hot blast inside a hot blast drying compartment, are adjusted so as to equalize the overall water content.
The maturing step for adjusting and equalizing the water content in each of the rice confectionery dough pieces is considered as an important step in that a crack and a curved profile during baking can be prevented. Conventionally, the maturing step has been realized by putting the rice confectionery dough dried by hot blast inside the drying compartment into containers, cardboard boxes and the like, and leaving them for several hours to more than 10 hours or dozens of hours, so that the water content between the interior and the exterior of a single rice confectionery dough piece and between each of the rice confectionery dough pieces are adjusted for an overall equalization of the water content.
Rice confectionery dough pieces are classified according to their thicknesses into thin (0.5 to 1.5 mm thick), middle-sized (1.5 to 3.0 mm thick) and thick (of thickness over 3.0 mm) pieces, and average durations of maturing for respective (rice confectionery) dough pieces are listed on the following table:
TABLE 1Optimal “maturing”Least “maturing” durationduration1) Thin pieces2 hrs12 hrs (half a day)2) Middle-sized pieces6 hrs24 hrs (one day)3) Thick pieces10 hrs 48 hrs (two days)
Least maturing duration on the above Table 1 refers to a duration under which a manufacture of rice crackers is barely possible and optimal maturing duration is normally applied for improving the maintenance of quality in the rice crackers.
This conventional and commonly known maturing step comprises the following steps: (first) releasing rice confectionery dough dried by hot blast in a drying compartment using a releasing conveyor; (second) dividing the dough into pieces and packing them into containers, cardboard boxes and the like; and (third) leaving them for several hours to more than 10 hours or dozens of hours. Therefore, it is problematic that the step requires labor and the maturing duration, as well as labor and time for picking up the rice confectionery dough pieces after the maturing step from the containers, the cardboard boxes and the like, and for arranging them in lines on a transporting wire mesh conveyor belt of a baking apparatus.
Therefore, the applicant of the present invention has proposed a process and an apparatus for manufacturing rice confectionery products, wherein the required labor and time accompanying the maturing step can be remarkably reduced. A commonly known document in this regard is JP Laid-Open Patent Application No. 2002-34460.
In a process for manufacturing rice confectionery products as disclosed in the Laid-Open Patent Application, a maturing step which is inserted between a drying step and a baking step of rice confectionery dough pieces is realized by adjusting the atmospheric temperature and the transfer speed of the rice confectionery dough pieces already subjected to the drying step, while transferring them to the baking step.
Furthermore, an apparatus for manufacturing the same comprises a hot blast drying compartment and a maturing compartment, which both are provided inside a drying compartment for the rice confectionery dough pieces.
The process and apparatus for manufacturing rice confectionery products are epoch-making in that the above-mentioned time and labor required for the conventional maturing step can be remarkably reduced, but, in case of thin rice confectionery dough pieces having a thickness of about 0.5 to 1.5 mm, a sufficient adjustment in water content cannot be achieved even by using the above-mentioned process and apparatus, so that there may occur, during baking, a crack, a curved profile or a skin formation wherein only the surface of a dough gets hard.
Such a problem is not limited to the rice confectionery products, but arises also in other kinds of thin confectionery pieces made from wheat, etc. during their manufacturing process.